U.S. Pat. Nos. 3,077,454 and 3,634,270, the teachings of which are specifically incorporated herein by reference, teach certain inhibitors which can be employed to reduce the attack of acidic media on metals in such processes as acidizing petroleum producing formations and in industrial cleaning operations. The corrosion inhibitor of the present invention is similar to those taught in these patents. However, it has certain unexpected characteristics not possessed by the general class of inhibitors taught in U.S. Pat. No. 3,077,454 and 3,634,270. For example, in U.S. Pat. No. 3,634,270 it is taught that a sulfur compound (allyl thiourea) must be employed in combination with the basic nitrogen inhibitor to provide an effective inhibitor.